Mobile phones for at least two frequency bands are already known. The Motorola Micro Tac 8900 mobile phone provides automatic shifting between the GSM 900 MHz band (global system for mobile communications) and the GSM 1800 MHz band.
From the EP 0 355 973 B1, a digital mobile phone is known. The digital mobile phone includes an antenna, a receiver input for receiving signals on a first frequency, and a transmitter output for transmitting signals on a second frequency, different from the first frequency. The digital mobile phones comprise a duplex type filter, having a reverse attenuation from the transmitter output to the receiver input. The duplex type filter is used to couple the antenna to said receiver input and transmitter output. The duplex type filter replaces thereby an antenna switch to couple the antenna to the receiver and the transmitter respectively, and its control logic.